Technical Field. This invention relates to a method and apparatus for manufacture of railway car body shells, and more particularly to a method and apparatus for manufacture of railway car body shells of substantially uniform dimension.
Background: The typical passenger railway car in use today ranges in length from 30 to 85 feet and can easily weigh between 20,000 pounds to 200,000 pounds. Weight reduction is a significant concern, and as a result, lightweight materials, including aluminum framing and outer skins or shells are preferred since the lighter the weight of the rail car, the more fuel efficient the passenger carrying operation can be.
The typical railway car shell is constructed around a basic sub frame component which can be generally described as a U-shaped sub frame assembly having two vertical sidewall posts interconnected by a curved carline which functions as a roof support frame member or roof truss. Each shaped frame member is individually crafted, and welded in place to the side sills of the floor assembly, and interconnected, one to the other, usually by welding interconnecting door and window headers and sills. A reasonable analogy is that the railway car shell is constructed in much the same manner as any stationary building structure which uses framing members such as wall studs and roof trusses and rafters. Once the car shell frame is assembled, the outer skin is attached and it is fixed in place to the underframe and the rail wheel bogies.
Each car shell is individually fabricated piece by piece. This takes considerable skill on the part of the craftsman in aligning and insuring that the side posts and carlines are properly placed to insure that the finished railway car shell is plumb and within dimensional tolerances. The problem is typically aggravated by the fact that the car shell frame is usually formed of stainless or carbon steel pieces which, when welded together, are often times distorted by the welding process and require restraightening and repositioning.
In the typical prior art assembly process each U-shaped frame sub assemblies of the car shell frame is individually positioned relative to the previously positioned car shell frame. As a result, the acceptable tolerances for error in positioning car shell frames are relatively large and depending on whether the craftsman consistently errs on the side of positioning the shaped frames too close together or too far apart, can result in a dimensional tolerance stack up which actually alters the length of the finished railway car shell. In practice, the measurement of finished railway cars has disclosed dimensional differences of up to fourteen inches in length within a collection of railway passenger cars that are all supposed to be a standard 85 feet in length.
As a result, efforts have been made in the past to prefabricate sub assemblies of the railway car shell frame to minimize the dimensional problems due to measuring positioning errors and heat-induced distortions of the frame induced by hand crafting the car shell frames. One such example is disclosed in Peterson, U.S. Pat. No. 4,337,708 which issued on Jul. 6, 1982.
Another problem in the prior art is the difficulty in fixing an exact, replicable location within the interior volume or space of the car shell for purposes of installing inside fixtures, such as overhead luggage racks, grab rails, toilet facilities and galleys. In the prior art, the identification of the center line of the car is accomplished by taking a series of side-to-side measurements along the interior length of the car. As is the case with the fabrication of the car shell frame, this type of work requires skilled labor and results in, for all practical purposes, hand crafted, individually manufactured railway cars.
Finally, because of the significant dimensional variances between car shell to car shell on a production line, the use of interior module construction techniques is usually not feasible. If car shells were of uniform and exact dimensions and incorporated uniform, identifiable coordinate location references, the use of modular construction for such things as sleeping compartments, overhead luggage racks, food galleys and toilet facilities and the like, would be feasible and would significantly reduce the cost of construction.
Accordingly, what is needed is an apparatus and a method for constructing car shell bodies wherein the original design and dimensions can be replicated time after time within close tolerances. Another object of this invention is to eliminate or reduce the requirement for individually fitting pieces of the car shell frame or car shell frame subassemblies one to the other, relative to the other.
It is also an object of this invention to provide a method and apparatus for quickly and easily checking each subcomponent frame parts, including roof car lines, side posts, window sills, side wall frame members, floor beams, and the like, to ensure that each is of the correct dimensional size, shape and silhouette. It is another object of this invention to provide a plurality of reference holes within each of the above-listed frame members for positioning each frame member within a template for determining correct size, shape and silhouette, and for positioning each frame member within a car body subassembly fixture for producing subassembly roofs, side walls and floors of uniform dimensional tolerance.
It is further an object of this invention to provide a plurality of reference holes in each of the car body frame members which can later be used as attachment points for car body accessories and as a method of determining location within the car body shell with regard to cartesian coordinates.